This invention relates generally to motor vehicle exterior lighting, and more particularly to an anti-glare system for vehicle headlights.
Certain service vehicles, such as school buses, delivery trucks, and waste disposal trucks for example, may at times operate during non-daylight hours. During non-daylight operation, turning the headlight switch on illuminates the headlights, and other exterior lighting such as taillights, marker lights, cab clearance lights, etc. The headlights may operate on either high-beam or low-beam, depending on the position of a headlight dimmer switch. Headlights that are operating on low-beam may be momentarily switched to high-beam by another switch, sometimes called a flash-to-pass switch. Both dimmer switch and flash-to-pass switch may be disposed in association with a mechanism that operates turn signal/hazard warning switches. That mechanism comprises a steering column mounted lever that possesses actuating features distinct from turn and hazard actuating features to thereby provide independent actuation of the dimmer switch and the flash-to-pass switch.
A vehicle may also have a daytime running light circuit that automatically operates the headlights at reduced intensity for daytime running whenever the vehicle is operating and the headlight switch is off. The voltage that is applied to each of the headlight filaments during daytime running is less than their nominally rated operating voltage, causing the headlights to illuminate at less than full nominally rated intensity. There are various daytime running light circuits that can provide such reduced illumination intensity.
When a vehicle, such as a school bus, is operating during non-daylight conditions and/or in foggy weather with its headlights on, and the vehicle stops to pick up or discharge students, headlight glare from the school bus may impair some portion of an oncoming driver""s field of view of the bus. The present invention relates to a novel anti-glare system for attenuating headlight glare during such conditions. It is believed that this can provide better visibility for the driver of the oncoming vehicle.
One aspect of the present invention relates to a motor vehicle headlight circuit or headlight module or circuit that is energized from a voltage source and comprises at least one headlight providing illumination of a field of view frontally of the vehicle, a headlight switch that is selectively operable to OFF and ON positions for selectively turning the at least one headlight off and on, and a main headlight circuit controlled by the headlight switch for operating the at least one headlight substantially at nominally rated operating voltage when the headlight switch is operated to ON position to illuminate the field of view at nominal illumination intensity. A reduced illumination intensity circuit can operate the at least one headlight at less than nominally rated operating voltage to illuminate the field of view at less than nominal illumination intensity when the headlight switch is in OFF position. A signal source is selectively operable to give a first signal for causing interruption of the main headlight circuit and the at least one headlight to operate at less than nominally rated operating voltage, and to give a second signal for causing no interruption of the main headlight circuit so that operation of the headlight switch to ON position is effective to operate the at least one headlight at nominally rated operating voltage.
Another aspect of the present invention relates to a motor vehicle comprising a voltage source, at least one headlight providing illumination of a field of view frontally of the vehicle, and a headlight control that is selectively operable to OFF and ON positions for selectively turning the at least one headlight off and on. A main headlight circuit is controlled by the headlight switch for causing substantially full voltage of the voltage source to be applied to the at least one headlight when the headlight control is operated to ON position to illuminate the field of view at a relatively full illumination intensity. A reduced illumination intensity circuit can cause substantially less than full voltage of the voltage source to be applied to the at least one headlight so that the field of view is illuminated at substantially less than relatively full illumination intensity when the headlight switch is in OFF position. A signal source is selectively operable to give a first signal that causes interruption of the main headlight circuit and substantially less than full voltage of the voltage source to be applied to the at least one headlight, and to give a second signal that causes no interruption of the main headlight circuit so that operation of the headlight switch to ON position is effective to cause substantially full voltage of the voltage source to be applied to the at least one headlight.
Still another aspect of the present invention relates to a motor vehicle comprising a voltage source, at least one headlight providing illumination of a field of view frontally of the vehicle, and a headlight control that is selectively operable to OFF and ON positions for selectively turning the at least one headlight off and on. A main headlight circuit is controlled by the headlight control for causing substantially full voltage of the voltage source to be applied to the at least one headlight when the headlight control is operated to ON position to illuminate the field of view at a relatively full illumination intensity. When the vehicle is not in motion and the headlight control is in ON position, a signal source gives a first signal for overriding the main headlight circuit by causing substantially less than full voltage of the voltage source to be applied to the at least one headlight so that the field of view is illuminated at substantially less than relatively full illumination intensity.
The foregoing, along with further features and advantages of the invention, will be seen in the following description and claims comprising disclosure of a presently preferred embodiment of the invention and depicting the best mode contemplated at this time for carrying out the invention. The disclosure includes drawings, as now briefly described.